This application represents the second competitive renewal for our Training in HIV Pathogenesis T32 program that supports 6 predoctoral and 3 postdoctoral trainees per year. Our program is based at the University of Pennsylvania School of Medicine, the Children's Hospital of Philadelphia and the Wistar Institute, which occupy a single, contiguous campus in west Philadelphia. Together, these institutions have one of the largest HIV/AIDS research programs in the country, with a funding base of >$40 million as determined by the NIH Office of AIDS Research. This level of funding enabled our Center for AIDS Research (CFAR) to successfully apply for Tier-2 NIH funding (i.e. $2.25 million annually) in both 2004 and 2009. Amongst the many individuals who study HIV/AIDS on our campus, a highly select group of 15 trainers are associated with this program. Because we are intent on having a well-focused training program in which our trainees benefit from our facilities and trainers, we place special emphasis on collaborative science and a commitment to training students and postdoctoral fellows. The cohesive nature of our training program is demonstrated by the fact that all 15 trainers have published papers with other trainers, that 11 of the trainers have significant involvement (>50K per year in direct costs) with jointly funded NIH grants with other trainers (a total of 11 funded grants, not counting the CFAR grant), that there are many joint lab meetings, and that our trainers participate in programmatic activities and minority-recruitment efforts. To date, a total of 42 trainees from 17 different laboratories have been supported by this T32, including 22 Ph.D. students, 4 M.D./Ph.D. students, and 15 Ph.D. postdoctoral fellows. Of our trainees, 49% have been women and 20% under-represented minorities. Of the 9 postdoctoral fellows who have completed their training and left Penn, two are in academics, 6 are working scientists in industry, including two in Merck's HIV integrase program and one in Merck's vaccine program. One former postdoctoral trainee leads a TB vaccine program at the AERAS Foundation. Of the 26 predoctoral trainees, 11 are still in training at Penn, 10 are doing postdocs in virology and infectious diseases at institutions that include Harvard (2 trainees), Emory, NIH (2 trainees), and UCSF, 1 is interviewing for a postdoctoral position, 1 is a scientist in industry, 1 has entered an MPH program due to a strong interest in global health, 1 is in law school and 1 left the program for medical reasons.